On July 19, 2012, a moderately powerful solar flare exploded on the sun’s lower right hand limb, sending out light and radiation. Next came a coronal mass ejection (CME), which shot off to the right out into space. And then, the sun treated viewers to one of its dazzling magnetic displays — a phenomenon known as coronal rain.
Over the course of the next day, hot plasma in the corona cooled and condensed along strong magnetic fields in the region. Magnetic fields, themselves, are invisible, but the charged plasma is forced to move along the lines, showing up brightly in the extreme ultraviolet wavelength of 304 Angstroms, which highlights material at a temperature of about 50,000 Kelvin.